High Speed Sheet Feeder Sheet Spacing System and Method

ABSTRACT

A document system and method of moving documents of a stack. The system operates to move documents by rotating a feed wheel and a transport wheel to move a document in a feed direction. The space between documents is maintained by controlling the speed of the feed wheel and the transport wheel independently.

FIELD OF INVENTION

The present invention relates to document and sheet feeding devices generally, and more particularly to document and sheet feeding devices that are capable of continuously feeding sheets to be sorted and further processed at high speeds, and more particularly still to a sheet feeding system and method for improving the speed and efficiency of such system by enabling more precise spacing between individual sheets in a set and between separate sets.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 is a block diagram illustrating a document feeder control system in accordance with the present invention.

FIG. 2 is a perspective top view photograph illustrating the position of the feed and leading edge sensors on the feed track in accordance with the present invention.

FIG. 3 is a perspective top view photograph illustrating the servo controllers of the present invention.

FIG. 4 is a chart summarizing the preferred paper travel speed ranges of the document feeder control system of the present invention.

FIG. 5 is a flowchart illustrating the steps in initializing the document feeder control system of the present invention.

FIG. 6 is a flowchart illustrating the post initialization steps in the document feeder control system of the present invention.

FIG. 7 is a flowchart illustrating the next steps in the document feeder control system of the present invention.

FIG. 8 is a flowchart illustrating the next steps in the document feeder control system of the present invention.

FIG. 9 is a flowchart illustrating the next steps in the document feeder control system of the present invention.

FIG. 10 is a diagrammatic illustration of the system at the time of initial power up.

FIG. 11 is a diagrammatic illustration of the system at the time of initialization.

FIG. 12 is a diagrammatic illustration of the system upon pre-feeding the paper sheets at speed 1.

FIG. 13 is a diagrammatic illustration of the system at the time of pre-feeding at speed 2.

FIG. 14 is a diagrammatic illustration of the system at the time of pre-feeding at speed 2 illustrating the separation between fed pages.

FIG. 15 is a diagrammatic illustration of the system with servo controller 2 at speed 3 and servo controller 1 at speed 1.

FIG. 16 is a diagrammatic illustration of the system with servo controller 2 at speed 3 and servo controller 1 at speed 1, with the paper being fed through the second set of transport wheels.

FIG. 17 is a diagrammatic illustration of the system with the feed wheel pre-feeding at speed 3.

FIG. 18 is a diagrammatic illustration of the system at the time of initialization again.

FIG. 19 is a diagrammatic illustration of the system at the time of pre-feeding at speed 1, and W=2.

FIG. 20 is a diagrammatic illustration of the system changing to speed 2.

FIG. 21 is a diagrammatic illustration of the system at speed 2.

FIG. 22 is a diagrammatic illustration of the system at speed 2.

FIG. 23 is a diagrammatic illustration of the system changed back to speed 1.

FIG. 24 is a diagrammatic illustration of the system back at speed 1.

FIG. 25 is a diagrammatic illustration of the system as it changes to speed 2 again.

FIG. 26 is a diagrammatic illustration of the system at speed 2.

FIG. 27 is a diagrammatic illustration of the system with servo controller 2 at speed 3 and servo controller 1 at speed 1.

FIG. 28 is a diagrammatic illustration of the system with servo controller 2 at speed 3 and servo controller 1 at speed 1.

FIG. 29 is a diagrammatic illustration illustrating servo controller 2 at speed 3.

FIG. 30 is a diagrammatic illustration servo controller 2 at speed 3.

FIG. 31 is a diagrammatic illustration of the system at the time of completion of a sheet set.

FIG. 32 is a diagrammatic illustration of the system set ready to initiate accumulation of the next sheet set.

FIG. 33 is a diagrammatic illustration of a prior art sheet feeder system.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best mode or modes of the invention presently contemplated. Such description is not intended to be understood in a limiting sense, but to be an example of the invention presented solely for illustration thereof, and by reference to which in connection with the following description and the accompanying drawings one skilled in the art may be advised of the advantages and construction of the invention.

FIG. 1 illustrates a diagrammatic view of a document feeder control system 10 adapted for use in accordance with the present invention. A stack of sheets or documents 14 to be fed or pulled in a feed direction indicated by arrow 15 is provided in close proximity to a feed wheel 18. Feed wheel 18 is preferably of a known type comprising a rotatable shaft having a plurality of rollers secured to the shaft, at least one of which rollers is in contact with, or which can be brought into contact with, bottom sheet or document 16 in stack of sheets or documents 14, such that when the feed wheel 18 is rotated it grips and pulls, or provides a feeding force, on sheet or document 16 in the feed direction 15. It will be understood that such feed mechanism is merely exemplary, and that depending upon the application, different types of feed mechanisms may be employed while still falling within the intended scope of the present invention. Also shown in FIG. 1 is a mechanism for further transporting sheets or documents 16 in feed direction 15 comprising a pair of transport wheels 24 and 32, which wheels are similar to feed wheel 18 in that they are preferably comprised of a shaft having a plurality of rollers secured to the shaft which when the shaft is rotated grip and pull, or provide a feeding force, on a sheet or document 16 in the feed direction 15. See also FIG. 2. It will be understood, however, that depending upon the application, a greater number of such shafts may be provided as part of the conveying mechanism, which shafts are also preferably joined together by O-ring belts 25 or the like secured to pulleys and extending between the rotatable shafts so that the rotation speed of wheels 24 and 32 is the same. At least one of such rotatable shafts is a drive shaft, and idler or guide rollers 27 are positioned adjacent wheels 24 and 32 such that sheets 16 fed by feed wheel 18 in feed direction 15 are received between transport wheels 24 and 32 and rollers 27 and transported to a downstream accumulation area or accumulator 29, after which each set or stack of sheets is further processed depending on the intended application by various of folding, stacking, mailing, or other mechanized processing equipment available in the prior art. As will be explained in detail below, the speed and accuracy of the feeding process by which sheets or documents 16 in stack 14 are conveyed along the feeding track by the feed wheel 18 and transport wheels 24 and 32 to accumulation area 29 and arranged in separate stacks for further processing by the sheet feeding system of the present invention.

As illustrated in FIGS. 3 and 10, feed wheel 18 is operably connected to a servo controller and servomotor 20, also referred to herein as “Servo #2,” that drives and controls the activation and deactivation and rotation speed of feed wheel 18, as controlled by the overall sheet feeder control system which includes a central processing unit (CPU) and RAM and ROM memory and which is implemented using software and/or hardware techniques known in the art. As shown in FIG. 2 and referred to in subsequent flowcharts and diagrammatic figures, downstream from feed wheel 18 is a first electronic document sensor 22, also known as the feed sensor and referred to herein as “Sensor A”, which detects the presence or absence of a sheet or document 16 as it is being fed in feed direction 15 and upon reaching or passing such sensor 22. “Sensor A” 22 may advantageously be an optical sensor of a type that should be known to those skilled in the art and generates an output signal whenever a sheet or document interrupts or is detected to be passing in the path of the sensor; however, “Sensor A” 22 may also be another type of sensor such as an ultrasonic sensor. Transport wheel 24 is situated directly downstream of “Sensor A” 22, and as indicated above, transport wheel 24 is connected to another transport wheel 32 further downstream by belt 25. Transport wheels 24 and 32 are operably connected to another servo controller and associated servomotor 26 (see FIG. 3) which is part of the overall feeder control system 10 and is referred to alternatively herein as “Servo #1.” As described below, depending upon the feed conditions the output signal of Sensor A may be used to control and adjust the rotation speed of Servo #1 or Servo #2, or both Servos #1 and 2 simultaneously.

Encoder 28 is operably connected to the shaft of transport wheel 24, and is used to measure the length of each sheet or document 16 being fed. Encoder 28 may be a standard shaft encoder with 600 pulse per revolution or other rotary pulse generator. A second electronic document sensor 30, also referred to herein as leading edge sensor or “Sensor B”, is situated on the downstream side of transport wheel 24, between transport wheels 24 and 32. Similar to “Sensor A” 22, “Sensor B” 30 is also advantageously an optical sensor that generates an output signal whenever a document is detected to be passing in the path of the sensor, but may be another type of sensor such as an ultrasonic sensor. Sensor B 30 is operably connected to encoder 28 such that the output signal of Sensor B activates encoder 28 to perform various functions such as resetting the encoder value to zero, initiating sheet measurement, and performing a check of the calculated encoder value. As explained in greater detail below, the combination of leading edge sensor 30 and encoder 28 connected to transport wheel 24 exactly measures the length of each sheet 16 as it is fed by the feeder, which information is used to configure the system to provide the desired separation between consecutive sheets being fed.

Transport wheel 32 carries sheets or documents 16 passed from transport wheel 24 to an accumulation area or accumulator 29, where a plurality of individual sheets or documents 16 intended to be grouped into a set or stack 36 is accumulated prior to be fed further down the feed track for further processing such as to a folding device for folding, and then to an enveloping machine and/or other processing apparatus in a manner known to those skilled in the art. Once a set has been accumulated, the next set to be accumulated is signaled or initiated.

A preferred manner of operation of system 10 will now be described with reference to the detailed steps in the flowcharts of FIGS. 5 through 9, as well as the sequential diagrams shown in FIGS. 10 through 33. In each of FIGS. 10 through 32, the presence or lack of arrow depictions in the feed and transport roller wheel drawings is indicative of whether or not such wheels are rotating and the direction of such rotation. Referring to FIG. 5, in Step 100, the system 10 is set or initialized in the manner now described. In Step 110 Servo #2 (or feed wheel servo controller 20) is activated at Speed #3, causing feed wheel 18 to rotate at a pre-set speed and in turn causing a sheet 16 to be fed, or pre-fed, from the bottom of the stack of sheets 14 in a feeding direction 15. This is illustrated in FIG. 11, in which only the feed wheel is shown rotating, in a clockwise direction. The distance sheet 16 is pre-fed in feeding direction 15 is determined in Step 120. More particularly, sheet 16 is pre-fed until it is detected by first electronic document sensor (Sensor A) 22. When “Sensor A” 22 detects sheet 16, feed wheel servo 20 (Servo #2) stops, causing feed wheel 18 to stop rotating (Step 130). Sensor A thus provides a fixed pre-feed point or starting point for sheet or document 16, which point is also referred to herein as “Alignment Point X”, and also is the alignment point for successive documents or sheets in the same set and additional sets. The starting point is mechanically adjustable according to the position of Sensor A.

FIG. 4 is a Servo Motor Speed Chart which summarizes the different speeds of Servo #1 and Servo #2, which are indicative of the rotation speeds of feed wheel 18 and transport wheels 24 and 32, respectively, in accordance with a preferred embodiment of the present invention. Speed #3 referred to above with respect to the speed of Servo #2 is a preferred paper feed speed available to Servo #2 and feed roller 18. More particularly, transport roller servo 26 (Servo Motor #1) has two available speeds; Speed #1 in which transport wheel or roller 24 has a paper travel speed of between 150-250 inches per second (ips), and Speed #2 in which the paper travel speed is greater than Speed #1 by 2.5-10%. In addition, feed roller servo 20 (Servo Motor #2) has three available speeds; Speed #1 in which the paper travel speed of feed wheel 18 is equal to between 150-250 inches per second (ips), Speed #2 in which the paper travel speed is less than Speed #1 by 2.5-10%, and Speed #3 in which the paper travel speed is less than Speed #1 by 75-90%. By varying such speeds in the manner described, the overall speed of feed system 10 is improved.

Referring again to FIG. 5, when in Step 130 the leading edge of sheet 16 is detected by first electronic document sensor (Sensor A) 22 and Servo #2 is stopped, as part of the pre-feed routine of the first page of the sheet set (Step 140), servo controllers 20 and 26 (Servo #1 and Servo #2) are both activated at Speed #1 (Step 150), which speeds are preferably the same, so that feed wheel 18 and transport wheels 24 and 32 are rotating at the same inches per second (ips) speed. Step 150 is illustrated diagrammatically in FIG. 12, in which both the feed and transport rollers are moving at Speed #1, causing first sheet 16 to be pre-fed forwardly in feed direction 15 until, as shown in FIG. 13, the leading edge of the first sheet 16 is detected by second electronic document sensor (Sensor B) 30 (Step 160). Once second electronic document sensor (Sensor B) 30 detects or is blocked by first sheet 16, in Step 170 the value of encoder 28 is reset to zero, and the encoder 28 begins measuring the length of sheet 16. In addition, in Step 180 a read logic circuit is initialized to enable a scanner to read a visual code, such as a bar code, on the document or sheet 16 if present.

Referring now to FIG. 6, the value measured by encoder 28 is then compared with a preset value (Step 200), which preset value is also described herein as “Separation Point Y.” If the value measured by encoder 28 is above the preset value or “Separation Point Y,” in Step 210 the speed of feed roller servo controller (Servo #2) 20 is reduced to from Speed #1 to Speed #3, which reduces the speed of feed wheel or roller 18 to 75-90% of Speed #1. The speed of transport roller Servo #1 is increased from Speed #1 to fastest Speed #2. Alternatively, the speed of transport roller Servo #1 may remain at Speed #1. Since transport wheel 24 is moving at Speed #2 or Speed #1 and feed wheel 18 is now moving at significantly slower Speed #3, as illustrated in FIGS. 15 and 16 sheet 16 a in contact with transport roller 24 is being conveyed in the feeding direction 15 at a faster rate than new sheet 16 b is being fed by feed roller 18, creating a gap 31 between such consecutive sheets having a predetermined width. Due to this speed change and the difference in speed of the feed and transport rollers, as shown in comparing FIGS. 15 and 16 the gap between sheets 16 a and 16 b has increased in FIG. 16 as compared to the early time shown in FIG. 15. It should be evident to those skilled in the art that the width of gap 31 or “Separation Point Y” as defined by encoder 28 may be selectively configured or controlled by system 10 to provide a desired separation between sheets. As sheet or document 16 is further conveyed in feeding direction 15 with time by transport wheels 24 and 32, eventually sheet 16 is no longer blocking Sensor A (Step 220), at which time if the speed of Servo #1 is Speed #2, the speed of Servo #1 controlling the speed of transport wheels 24 and 32 is reduced from Speed #2 to Speed #1 (Step 230). Movement of transport wheel 24 at a reduced speed due to the decreased speed of Servo #1, while at the same time feeder wheel 18 is rotating at an even further reduced speed (Speed #3) as controlled by Servo #2 and is initiating feeding of a second sheet, allows for precision separation between sheets in a set to be achieved by the feeder system 10, which allows the overall speed of the feeding process to be optimized.

Once the speed of Servo #1 has been reduced from Speed #2 to Speed #1 in Step 230 as triggered by the unblocking of Sensor A in Step 220, in Step 240, if the value measured by encoder 28 is below a preset value, encoder 28 continues measuring. However, once the value measured by encoder 28 is at or above such pre-set value, which is also referred to as “Stop Point Z,” in Step 250 Servo #1 26 is stopped, stopping transport wheels 24 and 32. Feed wheel 18 continues to rotate, however, and a second sheet or document 16 b is conveyed by feed wheel 18 from stack 14 in feed direction 15, until it is blocking Sensor A or “Alignment Point X” (Step 260), which triggers Servo #2 and feed wheel 18 to stop again (Step 270), similar to Steps 120 and 130 described above. This is illustrated diagrammatically in FIG. 17, where Servo #1 has stopped transport wheels 24 and 32 as well as sheet 16 a are not moving, and in addition new sheet 16 b has been pre-fed at Speed #3 to Sensor A or Alignment Point X, which as shown in FIG. 18 causes Servo #2 and feed wheel 18 to also stop, completing initialization of the system 10. Alignment Point X thus serves the important function of providing a predicable starting or alignment point for sheets being fed by the feeder system 10.

Referring next to FIG. 7, in Step 310 the system has now been initialized and is waiting for a start signal, illustrated diagrammatically in FIG. 18. As used herein Set Count “W” refers to the desired number of sheets to be collected into a group from either a fixed sheet count that has been pre-set by the operator using an input device of a type known to those skilled in the art, or a variable count based on visual code information that is printed on the sheets. In Step 320, the sheet Set Count that is expected for the sets of sheets is input into the system, and in Step 330, both transport roller Servo #1 and feed roller Servo #2 are activated at Speed #1. This is also illustrated diagrammatically in FIG. 19, in which for exemplary purposes the Set Count W is indicating as equaling two sheets (W=2).

Second sheet or document 16 b is fed by the rollers in the feed direction 15 until Sensor B is blocked by the sheet (see FIG. 20), which causes encoder 28 to reset to zero and initiates measuring of sheet 16 b (Step 350). In addition, in Step 360 a read logic circuit is initialized to enable a scanner device to read any visual coded information on the sheet or document, such as a bar code, being fed in the case of a variable sheet count. Encoder 28 continues measuring the sheet or document until in Step 370 the value measured by encoder 28 is at or above Separation Point Y, after which in Step 380 the speed of transport roller Servo #1 is increased from Speed #1 to fastest Speed #2, shown in FIG. 21, and in addition the speed of Servo #2 and feed rollers 24 and 32 is simultaneously decreased from Speed #1 to Speed #2. The speed change is initiated when sheet or document 16 b is no longer being gripped by feed wheel 18, as is indicated diagrammatically by comparing FIGS. 19 and 20. This change in speed of Servo #1 to a faster speed and Servo #2 to a slower speed allows for a controlled separation of the sheets during processing. The increase in such gap with time is evidenced in FIG. 22, where a more substantial gap is shown between sheet or document 16 b held by transport roller 24 and sheet or document 16 c held by feed wheel 18 as compared to the slightly earlier arrangement shown in FIG. 21. Then, in Step 390, sheet Set Count “W” is incremented to the next number according to the count of sheets to be included in the set.

Referring now to FIG. 8, in Step 410 if the sheet Set Count “W” is complete, the system proceeds as described in Steps 510-570 shown in FIG. 9 and discussed in detail below. If set Sheet Count “W” is not complete, then as shown in FIG. 8 system 10 monitors whether or not Sensor A is unblocked (Step 420). If yes, which arrangement is illustrated diagrammatically in FIG. 23, then in Step 430 the speed of Servo #1 is decreased back to Speed #1 and the speed of Servo #2 is increased to Speed #1, so that the rotation speeds of feed wheel 18 and transport wheels 24 and 32 are equal again. Once the speeds are adjusted, in Step 440 and the system checks again if Sensor B is unblocked by document or sheet 16 b, and when Sensor B is unblocked (see FIG. 23), in Step 450 the value calculated by encoder 28 is checked by the system to see if the total length of the sheet is correct. If yes, in Step 460, the visual code data on a sheet, if any, is checked to see if any set errors occurred. If the total length is correct and no visual code data errors are detected, the system repeats the sequence of steps starting from Step 340 described above with respect to FIG. 7, wherein the control system again monitors in Step 340 if Sensor B is blocked by the next sheet or document 16 c, and once Sensor B is blocked, as shown in FIG. 25, in Step 350 encoder 28 is reset and the length of the next sheet is measured. The system repeats Step 340 through Step 390. In Step 380 the speed of Servo #1 is increased to Speed #2, and the speed of Servo #2 is decreased to Speed #2. Such transition is illustrated in FIGS. 25 and 26. Then, in Step 410 if the Sheet Set Count W is incomplete, Steps 420 through 450 are repeated. In addition, in Step 430 when Sensor A is unblocked by the next sheet or document, the speed of Servo #1 is decreased to Speed #1 and the speed Servo #2 is increased to Speed #1. If in Step 450 or Step 460 an error is detected, instead of returning to Step 340, in Step 470 the system 10 initiates a system error routine and Servos #1 and #2 are both stopped.

Referring now to FIG. 9, where in Step 410 (FIG. 8) sheet Set Count “W” is complete, system 10 proceeds to Step 510 in which the speed of Servo #1 is decreased to Speed #1, and the speed of Servo #2 is reduced to Speed #3. This is illustrated in FIGS. 27 through 29, where the increase in the gap between sheet or document 16 c being carried by transport wheels 24 and 32 and sheet or document 16 d still in the feed wheel 18 with time is evident. Then, in Step 520, the value of encoder 28 is monitored to determine whether or not such value is at or above a predetermined value, which value is referred to herein as “Stop Point ‘Z.’” When the value measured by encoder 28 reaches “Stop Point ‘Z’”, Servo #1 is stopped, which is illustrated diagrammatically in FIG. 30 where only feed wheel 18 is rotating. Stop Point “Z” aligns sheet 16 b in transport roller 32 for a programmable stopping point of the first page of the next set. Once Servo #1 is stopped, system 10 monitors in Step 540 whether Sensor A is unblocked; when unblocked, in Step 550 the completed Sheet Set should now be in Accumulator (see FIG. 31). In Step 560 the system again monitors whether Sensor A is blocked by sheet or document 16 d, and when Sensor A is blocked, in Step 570 and as shown in FIG. 32, Servo #2 (feed roller servo 20) also stops, and sheet or document 16 d is stopped at Alignment Point X (dictated by Sensor A). This again aligns the first sheet in the next set for feed sheet processing with a predictable starting point. The system 10 thus continues in such manner until all of the designated sets of sheets 16 have been successfully accumulated.

FIG. 33 illustrates a typical prior art system whereby the feed wheel is controlled by an electromechanical clutch. In addition, there is a sensor positioned after the initial transport wheel, which is operated at a constant speed using a DC motor arrangement. FIG. 33 illustrates the basic steps in such prior art accumulating arrangement system. Upon receiving a start signal, the system starts feeding the sheets using said electromechanical clutch to control the feed wheel. When the sheet reaches the transport wheel and is detected by sensor 1, the feed wheel clutch is disengaged, is the sheet set count is complete, feeding of sheets is stopped as the complete sheet set should be in the accumulator. If the sheet set count is not complete, once sensor 1 is unblocked, the feed wheel clutch is engaged again to feed another sheet. Such process repeats until the sheet set count is complete.

In contrast, at certain times during the feed process of the present invention, Servo #2 is directed by the system to operate at a speed considerably slower than the speed of Servo #1 during the such feed process. By Servo #1 driving the feed wheel 18 to turn at such considerably slower speed allows for precise control of the feed process, and is designed to create a larger gap between sets, and also correctly positions the next piece from the feeder. In addition, the system 10 also directs a change in speed of Servo #1 and Servo #2 from Speed #1 to Speed #2, where the speed of Servo #1 is increasing while Servo #2 is decreasing in speed. This also allows for even greater control of the spacing between sheets both in the same set and between the last sheet in the set being accumulated and the next sheet in the set to be accumulated.

In U.S. Pat. No. 6,533,264 issued to M. N. Tranquilla on Mar. 18, 2003 entitled “Constant Space Document Feeder,” discloses an mechanism for generating a predetermined feed spacing between consecutive documents that is independent of the document length, wherein the feed wheel speed is reduced to an adjustment speed for an adjustment time period, and then is increased after the adjustment time period has expired. The adjustment speed and time period are determined by an adjustment module, wherein the trailing edge of a first document and leading edge of a second document are detected, which gives an initial feed spacing, and then the feed wheel speed is adjusted to give a predetermined or desired spacing. Tranquilla does not achieve the amount of control over the feed system that is achieved with the multiple speed system of the present invention.

U.S. Pat. No. 7,635,127 issued to K. Kuse on Dec. 22, 2009, entitled “Sheet Feeding Apparatus,” discloses a sheet feeder including rotation speed controller for the adjusting the speed of a separation roller used to feed sheets from a stack between a first speed and a second speed. In particular, the first sheet is fed at a slower rotation speed than subsequent sheets. The primary purpose of the Kuse patent is to prevent leading edge folding of a document during feeding during copying or the like using an automatic document feeding apparatus.

While the present invention has been described at some length and with some particularity with respect to the several described embodiments, it is not intended that it should be limited to any such particulars or embodiments or any particular embodiment, but it is to be construed with references to the appended claims so as to provide the broadest possible interpretation of such claims in view of the prior art and, therefore, to effectively encompass the intended scope of the invention. As used throughout, ranges are used as shorthand for describing each and every value that is within the range. Any value within the range can be selected as the terminus of the range. In addition, all references cited herein are hereby incorporated by referenced in their entireties. In the event of a conflict in a definition in the present disclosure and that of a cited reference, the present disclosure controls. 

What is claimed is:
 1. A document system for a document, including: a feed servo controller; a feed servo motor controllable by the feed servo motor; a feed wheel adjustably rotatable by the feeder servo motor to move the document in a feed direction; a feed sensor downstream of the feed wheel in the feed direction and capable of detecting the presence of the document; a transport servo controller; a transport servo motor controllable by the transport servo controller; transport wheels downstream of the feed wheel and the feed sensor in the feed direction, wherein at least one of the transport wheels is adjustably rotatable by the transport servo motor to continue to move the document in the feed direction; a transport sensor downstream of one of the transport wheels in the feed direction and capable of detecting the presence of the document; an encoder operably connected to a transport wheel to measure the length of the document; and wherein the rotational speed of the feed wheel and the rotational speed of the transport wheels are controllable independently.
 2. The system of claim 1, further including a stack of documents.
 3. The system of claim 1, including two transport wheels connected together for rotation, one of the transport wheels capable of driving the other transport wheel.
 4. The system of claim 1, further including an accumulator for collecting the document after being fed by the transport wheels.
 5. The system of claim 1, wherein more than on transport wheel is adjustably rotatable by the transport servo motor.
 6. The system of claim 1, further including a processor and wherein the feed sensor produces an output signal indicative of the detection of the document.
 7. The system of claim 6, wherein the feed servo motor is controlled by the feed servo controller depending on the output signal from the feed sensor.
 8. The system of claim 1, further including a processor and wherein the transport sensor produces an output signal indicative of the detection of the document.
 9. The system of claim 8, wherein the transport servo motor is controlled by the feed servo controller depending on the output signal from the transport sensor.
 10. The system of claim 1, wherein the transport sensor is operably connected with the encoder such that an output signal of the transport sensor activates the encoder.
 11. The system of claim 1, wherein the feed wheel is rotatable at multiple predetermined speeds.
 12. The system of claim 1, wherein the transport wheels are rotatable at multiple predetermined speeds.
 13. The system of claim 1, the document further including a visual code, the system further including a scanner to detect the visual code.
 14. A method of moving documents of a stack, including: rotating a feed wheel to move a document in a feed direction; rotating a transport wheel downstream of the feed wheel to continue to move the document in the feed direction; rotating the feed wheel and the transport wheel to move additional documents; and maintaining a space between the documents moving in the feed direction by controlling the speed of the feed wheel and the speed of the transport wheel independently.
 15. The method of claim 14, wherein rotating the feed wheel further includes rotating the feed wheel at a first feed speed to initiate moving a document in the feed direction to a first alignment point.
 16. The method of claim 14, further including: rotating the feed wheel at a first feed speed; detecting the presence of a document at a first alignment point and then stopping the feed wheel; rotating the feed wheel at a second feed speed that is faster than the first speed; rotating the transport wheel at a first transport speed that is the same as the second feed speed; and wherein maintaining the space between documents includes: determining if the document is at a predetermined position along the feed direction; and if the document is not at the predetermined position, adjusting the speed of at least one of the feed to move the next document slower and wheel and the transport wheel to move the document faster.
 17. The method of claim 16, wherein adjusting the speed of at least one of the speed wheel and the transport wheel includes at least one of: decreasing the speed of the feed wheel to either the first feed speed or a third feed speed that is slower than the first feed speed and slower than the second feed speed; and increasing the speed of the transport wheel to a second transport speed.
 18. The method of claim 16, wherein adjusting the speed of at least one of the speed wheel and the transport wheel is done after the document is past the feed wheel.
 19. The method of claim 16 wherein determining if the document is at a predetermined position includes measuring the length of a document to pass the predetermined position.
 20. The method of claim 16, further including: determining if the document has moved past the first alignment point; and if the document has moved past the first alignment point, rotating the feed wheel at the second feed speed and rotating the transport wheel at the first transport speed.
 21. The method of claim 14, including: determining the number of documents to move past the predetermined position; if the number of documents is equal to or greater than a set count value: stopping the rotation of the transport wheel; rotating the feed wheel at the first feed speed to move a document to a first alignment point; and detecting the presence of a document at the first alignment point and then stopping the feed wheel.
 22. The method of claim 14, including: determining the number of documents to move past a predetermined position; measuring the length of a document that has passed the predetermined location; if the number of documents is less than a set count value, determining if a document is located at a first alignment point; if no document is detected at the first alignment point: rotating the feed wheel at the second feed speed; and rotating the transport wheel at the first transport speed; determining if a document is located at the predetermined location; if no document is detected at the predetermined location, determining if the measured length of the document is correct; and if the measured length of the document is incorrect, initiating a system error routine and stopping both the feed wheel and the transport wheel.
 23. The method of claim 22, wherein: the documents include a visual code; and if no document is detected at either the first alignment point or the predetermined location and if the measured length of the document is correct, scanning the visual code on a document to determine if a set error occurred; if a set error occurred, initiating a system error routine and stopping both the feed wheel and the transport wheel.
 25. The method of claim 14, further including rotating the feed wheel at the second feed speed and rotating the transport wheel at the first transport feed after a document passes the first alignment point. 